What is it about Christy Wilhelmi's three-minute tip-of-the-week podcast Gardenerd that makes it feel like essential listening? Is it that it's so short and informative? Or maybe that Wilhelmi's pealing bell voice makes everything garden-related -- even getting rid of pesky powdery mildew -- sound easy? Whatever it is, just as the former private school fundraiser turned full-time professional garden expert was preparing to start another draft of a gardening novel she'd been working on, Massachusetts-based Adams Media commissioned her to write a how-to handbook.

Published last month, it's called Gardening for Geeks, and has a subtitle that comes with a promise: DIY Tests, Gadgets, and Techniques That Utiltize Microbiology, Mathematics, and Ecology to Exponentially Maximize the Yield of Your Garden.

Recently we spoke to Wilhelmi, who held forth on all manner of garden-related subjects, including the best starter crop for newbie gardeners, why growing your own grain might be ultimately unsatisfying, and what she discovers during house calls.

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Squid Ink: Is there really such a thing as a black thumb?

Christy Wilhelmi: A lot of people who come to me say they have a black thumb. I think with enough information they develop the confidence to at least turn their thumb towards green. As someone who has killed just about every houseplant she's ever owned, I know that there are some things you're just good at -- and some things you're not good at. If you stick to the things you're good at, you won't always have black thumb.

SI: What are people doing or not doing that transforms them into plant-killers?

CW: General neglect: Some people over-water, but mostly people forget to water. It's out of sight, out of mind. A lot of people just don't feel confident to trust their instincts. In my classes and in the book, which is based on the material I teach in my classes, people can find the confidence to say, "Okay! I can do this! I can experiment!"

SI: Success breeds confidence. What is a starter crop that can turn every aspiring gardener into a braggart?

CW: Beets. Even though I don't like beets -- I don't like how they taste -- they're so easy to grow and they make me feel like such a good gardener. For brand-new people lettuces are also great; things like radishes and arugula sprout in three days or so.

SI: Beets? Our experience with root vegetables is that the leaves are beautiful, but the bulb ends up looking like a wizened, gnarly fist.

CW: Right. That can be true with carrots and parsnips too. We don't necessarily have the frost that creates the sweetness in root crops or the right soil conditions. But first of all, I grow all my root vegetables in the fall. They tend to do better than in the spring. And you end up with beautiful, colorful greens in the garden and even if the beets don't form, you still have the pretty top of the beets and they hardly get any pests. That's another reason why I like to recommend them.

SI: Let's rewind for a second. You said people come to you. Are you not just a podcaster and an author, but a plant doctor as well?

CW: As part of my business, Gardenerd, I teach people how to grow their food and I do consultations.

SI: As in house calls?

CW: That's correct.

SI: What's a typical diagnosis?

CW: A lot of times they haven't taken the time to really, really condition their soil. Here in L.A., we either have clay soil or really sandy soil. When you add a lot of compost to that the plants grow a lot more easily. People don't know that [they need to condition their soil] so they have sort of half-baked results and then they wonder why.

So we start at the soil level, amend from there and then they experience a much better harvest from that point. Other mistakes people make are: over-watering and forgetting to put plant markers to denote where they planted what so they can't tell if it is something they planted or a weed.

SI: How long is a typical check-up, Dr. Wilhelmi?

CW: Most people need an hour -- and I throw a lot of information at them. They take notes, I take notes, and then I send a follow-up email that answers any questions I couldn't answer on site. That keeps them busy for a couple of months. If somebody wants to get a soil test, I'll suggest a couple of options: a hand-held soil test kit from a nursery or online or to take a sample and to send it to a lab and have it analyzed. Sometimes we have heavy metals in our soil and that can be either toxic to us or disruptive to the plant growth process. For people who really want to know what's going on in their gardens I recommend both things.

SI: We didn't know until reading Gardening For Geeks that we're supposed to be frightened of garden hoses. Some aren't drinking water safe, right?

CW: Right! No one did! We assume everything that is sold to us is safe. A report came out from Healthystuff.org that sampled 179 garden products in 2009 and found that more than 30 per cent contained lead in levels that exceeded amounts allowed for children's products. The shock that the cute little gloves with nubbies on them have lead in them? That's really scary. We do have to be careful because we're at the top of the food chain.

SI: The idea of a 3-minute service podcast is pretty genius: Who doesn't have 180 seconds to find out that after the cooking water you used to hard-boil your eggs has cooled you should pour it on tomatoes, potatoes and Chayote squash because it is calcium-rich?

CW: In February of 2008 when[I first started doing the podcast] there was enough information out there that short podcasts are popular. Just like you said, it doesn't require a lot of time. And I certainly didn't have enough time to produce an hour-long podcast every week. It was pretty straightforward to put something together that was relevant to something happening here in California and help people stay interested in gardening. My first topic was Seed Starting for a Better Tomorrow.

SI: What's the most controversial 3-minute podcast you've ever done?

CW: It had to have been the one about Prop 37. I tried very hard to stay out of politics when it comes to my garden stuff. But it's almost impossible not to get political when you're talking about food. The government is doing all this stuff to approve genetic engineering and proliferate all these pesticides and herbicides. For example, the European Union just announced that they're banning all pesticides that have been killing bees. Do you think we're going to do that any time soon?

When the Prop. 37 thing was happening, we thought, "This is a no-brainer." Then the last two weeks of the campaign, Monsanto dumped $50 million in negative ads against the proposition. I was mortified. I thought, "Okay, people. I have some influence here. I'm going to tell you what to think."

SI: So what happened?

Christy Wilhelmi in her garden

courtesy: Christy Wilhelmi

CW: Some people unsubscribed. You can never please everyone.

SI: What did the pre-Gardenerd Christy Wilhelmi do for a living?

CW: I was working for a private school in fundraising. I was doing good work but my job had changed a number of times and I had entirely new skill sets and I'd been overlooked for promotions or raises during the entire ten years that I was there. It was really unsatisfying in that way. It was that combined with my desire to grow my own food and have more control over what I was growing. I've been growing my own food for twenty years.

SI: At home or at Ocean View Farms Community Garden?

CW: It was mostly at the community garden then in 2007 we bought a house. The very first thing we did was put in a vegetable garden in the back yard.

SI: What do you grow?

CW: Oh gosh. Got some time?

SI: Yes.

CW: I'm growing strawberries, corn, asparagus, four different kinds of carrots, two different kinds of kale, two different kinds of cucumbers, celery, and three different kinds of squash. I just harvested garlic. I'm growing millet, which is an interesting experiment for the season. I'm growing sixteen different kinds of tomatoes, half here and half in my community garden plot. Three different kinds of peppers and I will be planting edamame and spinach. I don't buy bulb onions -- I just pick them up at the farmers market.

SI: What is something that is so hard that it's just not worth even trying to grow?

CW: If you're going to grow grains, you do need to have enough space to make it worthwhile. In a four by four square foot bed you end up with about two cups worth.

SI: Raccoons. Ugh. How do you get rid of them?

CW: I know people in the canyons who use deer fencing, but left a little loose so they can't climb over it because it's wobbly. We cover the strawberry patch with bird netting and that keeps them out. We don't have raccoons -- but we have squirrels and we have rats. As long as I don't meet up with [rats], I'm okay with them.

SI: What is your take on the raccoon-deterrent that involves an AM/FM radio set on a very low volume to a talk station so they think that people are having a non-stop, sort of murmuring gabfest in your back yard?

CW: I've read about that. My understanding is that they eventually figure it out. It's like, "Yeah, yeah. Whatever."

SI: What's an essential gardening gadget?

CW: You can get away without a lot of tools but you have to have a good pair of pruning shears. My preference is Felco #6 [classic pruners] for small hands.

SI: What is a total waste of money?

CW: Compost starter. When people start a compost bin there is this stuff called something like compost activator. It's totally unnecessary. If you have soil under your feet you have compost starter. The idea is that if you pick up a handful or shovelful of soil and throw it in your compost bin, that soil is inoculated with billions of micro-organisms that will get to work breaking down your compost right away. Throw a handful of soil in and water it down and that's all the compost starter you ever need.

SI: How do you know if your seeds are too old?

CW: Do a germination test. You can lay out a paper towel, put ten seeds on that paper towel about an inch apart, fold it up and then run it under water then put it in a plastic bag on top of your fridge or wherever it's warm and out of the sunlight. Wait the number of days that it says it takes to germinate on the seed packet. Then check them. Some people say that if less than half of them sprout you can toss them and get new seeds. For me, how you store your seeds determines how long your seeds last. I have seeds that date back to 2000. Except for onion seeds, they'll last as long as you keep them out of sunlight, dry and in a cool location.

SI: Where do peppers fit on the difficulty scale when it comes to growing them from seed?

CW: A lot of people have trouble getting peppers to grow. There are pepper fanatics who spend their lives studying how to grow peppers in the right way. I've had my share of difficulty -- especially during cool summers when they just sit there and don't do anything. Germination is an issue. You could try germinating them in a paper towel and then planting the sprouts. You can actually sprout strawberries that way: Just scraping off the seeds.

SI: What nurseries are the best for starts?

CW: I'm very partial to Marina Garden Center because they're stuff is beautiful. When Armstrong's -- either in Santa Monica or in Westchester -- is on their game, I start there because they have organic.

SI: You've warned us against cinderblock planters. What about ones made of concrete?

CW: Concrete is fine. The reason why I warned against cinderblock is because they use fly ash which often contains heavy metal.

SI: On a scale of one to ten, how great of a place is Mar Vista -- where your community garden is located -- to grow vegetables?

CW: It depends on what kind of year we're having. In terms of being able to grow year round, it's a total ten. We're just blessed with this amazing climate where we can grow just about anything year round. We've had a few really cold summers and I didn't take my jacket off at all and that was, like, a five or a four. But most of the time, we have a heat wave that lasts three weeks and then we're done. We should not complain.